Rail fissure detector car



Sept 8, 1936 H. C. DRAKE ET AL RAIL FISSURE DETECTOR CAR Filed July 14,1934 0.1. VOLTAGE 3maentors Ha rcawi: wake Fwd raddan Gtto neg PatentedSept. 8, 1936 UNITED STATES PATENT OFFICE RAIL FISSUBE DETECTOR CARApplication July 14, 1934, Serial No. 735,100 9 Claims. (01. 177-311)This invention relates to rail fissure detector cars adapted to travelover the rails in track and detect and mark for identification thoserails having fissures or other internal defects. More particularly, theinvention relates to the type of fissure detector mechanism embodied inthe Sperry rail fissure detector cars. In said cars, the railisenergized, as the car travels along the track, by means of currentpassed therethrough to set up an electromagnetic field surrounding therail, and any irregularities in said field due to internal defects aredetected by means of a plurality of induction coils carried at a fixeddistance above the rail. On entering a region of fiaw one 01' said coilswill cut a different number of lines of force from the other coil andthis will generate a differential E. M. F. which after being suitablyamplified may be caused to operate one or more indicating means. Suchindicating means in the Sperry cars take the form oi! one or more pensoperating on a travelling chart to make a record thereon and also one ormore paint guns for marking the location of the fissure in the rail andmarking the general location of the flssured rail in track. Therail-and-track-marking means should possess diflerent characteristics.The rail-marking means should make a short paint mark as nearly aspossible'at the exact location of the fissure, while the track-markingdevice should make a relatively large mark in the center of the track onthe ties and road-bed between the rails.

This invention has for its principal object the provision of means forinsuring constant operation of the rail-marking means so that regardlessof the degree 01' fissure or the extent of the induced E. M. F. causedby the fissure, the mark placed upon the rail in the vicinity of thedefect will be relatively short and always or the same size.

It is a further object of our invention to provide a novel arrangementfor insuring operation of the road-bed-marking means whenever therail-marking means is actuated.

Further objects and advantages oi. this invention will become apparentin the following detailed description thereof.

In the accompanying drawing,

Fig. 1 is a side elevation of a portion of a Sperry rail flaw detectorcar having our invention embodied therein.

Fig. 2 is an electric wiring diagram illustrating the principle involvedin our invention.

Referring to Fig. 1 of the drawing, there is disclosed a portion of thecar body ll of a Sperry rail fissure detector car, from which issuspended the detector mechanism consisting essentially of a currentbrush carriage ll having sets of current brushes l2 and I3 for supplyingcurrent to the rail from a generator G mounted within the car body. Thissets up an electromagnetic field surrounding the rail and said fieldwill be homogeneous except in the region of fiaw, where it will bedistorted. Such distortion may be detected by means of a pair 01'induction coils l4 supported on a carriage l5 at a constant distanceabove the o railhead so that on encountering a region of fiaw, first oneand then the other 0! said coils will out a different number of lines01' force to generate a difi'erential E. M. F. which after beingamplified by an amplifier A may operate a pen P on a chart, not shown,to give an indication of the presence of a flaw. Said pen P may beoperated from the amplifier A by causing the output 01 said amplifier toenergize a coil 20 to attract an armature 2| and break a set of contacts22 controlling the circuit of pen coil 23. The detector carriage l5 maybe supported on the rail by means such as rollers 25 and said carriagemay be mounted on the current brush carriage H by means such as looselyfitting bolts 26 and springs 21, whereby said detector carriage mayadjust itself to the variations in surface of the railhead. The currentbrush carriage H may be supported on the rail by means such as wheels28. Said current brush carriage is normally held in elevated position bymeans of cables 29 and springs, not shown, but when said carriage is tobe lowered into engagement with the rail, fluid pressure is supplied tocylinders 30 to depress pistons 3| which are pivotally connected to andsupport the carriage 30 I i.

At the same time that the impulse from amplifier A actuates the pen P,it also operates rail-marking means in the form of a paint gun 40, androadbed-marking means in the form of a paint gun 4|. This isaccomplished by means of a relay l2 controlling a paint supply valve 43which in turn controls the supply of paint passing through rail-markingmeans It and a relay 4 controlling valve 45 which in turn con- 40 trolsthe supply of marking fluid passing through gun ll. These paint gunrelays 42 and N are connected in circuit with pen coil 23 in such mannerthat regardless of the input to amplifier A the paint gun 40 will beactuated to a constant to and predetermined limited degree and,secondly, the paint gun 4| will be actuated whenever paint gun 40 isactuated.

Referring to the wiring diagram of Fig. 2, I have illustrated a methodfor obtaining a constant, predetermined, limited energization oi paintcoil 42 regardless of the input to amplifier A or the extent ofenergization or de-energization of pen coil 23. For this purpose, Icause the opening of contacts 22 and consequent deenergization of pencoil 23 to induce by means of induction coils 41 and 48 a potentialwhich is impressed upon the grid 50 of a gaseous discharge tube 5l. Saidgrid 50 is normally connected to the negative side oi a battery 52 andas 50 long as it is negative to a predetermined degree no current willpass through the tube, in ac-- cordance with the well known principlesgoverning the operation of this tube. When, however, a potential isimpressed upon the grid 50 to render the same less negative, currentfrom the D. C. voltage source is permitted to flow between the anode 53and cathode 54 of said tube to energize the coil 42 and charge acondenser 55 which is in the said D. C. circuit. The flow of currentthrough said tube will charge condenser 55 not only to a voltage equalto the voltage of the D. C. source of supply, but to a higher voltage byreason of the inductance of coil 52. This excess voltage impressed oncondenser 55 will cause the current to cease flowing through the tubeand thus de-energize paint coil 62. It will thus be seen that only forthe brief interval during which the current surges through the gaseousdischarge tube and charges condenser 55 will paint coil 42 be energized,and it will be further seen that the time of energization will beconstant each time that the above described action takes place, so thatwe are enabled to obtain a brief actuation of the paint coil which willr wult in a short, well-defined paint mark on the rail, of constantlength, at each actuation of the paint gun 50.

As soon as the current through tube 5! has ceased to flow, it isdesirable that the condenser 55 be discharged quickly in order that thedevice shall be ready for another actuation in response to the presenceof a flaw. Ordinarily, the condenser 55 has shunted across it a highresistance 56 so that the current may gradually leak ofi said condenser.This, however, takes too long an interval of time for rail testingpurposes, since the car travelling along the rails may encounter anotherfissure within a very short interval of time after finding one fissure.We have therefore provided the following novel arrangement for quicklyde-energizing condenser 55. For this purpose there is provided a shuntcircuit around condenser 55 which includes lead 55, coil M of apolarized relay, and lead 65. When condenser 55 begins to discharge,current flows through the shunt circuit in the direction of arrow B andwill energize coil BI to act upon its core 62 and close a circuitbetween contacts 55 and to impress a voltage from the D. C.

voltage source upon a grid 66 of a triodevacuum tube 61 which is in ashunt circuit by way of anode 68 and conductor 69 around condenser 55.Said tube normally is of high resistance, while the condenser 55 ischarging, but as soon as coil 6| is energized to close contacts 63 and64 and a potential is impressed upon grid 66, the resistance of tube 61is immediately lowered so that the condenser 55 may discharge throughthe said shunt circuit. Thus the tube 61 performs all of the functionsof high resistance while condenser 55 is charging but does not have theinherent disadvantage of requiring a long time for discharging thecondenser because the said tube 6'! by the arrangement describedconverts itself into a. low resistance at the proper instant todischarge condenser 55 quickly.

We have also provided an arrangement whereby energization of paint gun40 will result in energization also of paint gun 4!. When current flowsthrough the tube 5! to energize coil 42 and charge condenser 55, currentwill flow through the shunt path in the direction of arrow C, which 'isa. direction opposite to that of arrow B, and will oppositely energizecoil 65 to cause contact 53 to engage contact 18 and thus impress apotential upon the grid 16 of a triode vacuum tube ll which is in thecircuit of a D. 0. Voltage supply. The characteristics of tube 11 aresuch that low current flow is maintained in the said circuit until thepotential is impressed upon grid 76, whereupon current flows by way ofplate 18 tocoil M in the D. C. circuit and thus actuates paint gun valveof paint gun 4|. The contact 63 is normally centralized by any suitablecentralizing spring arrangement 80.

In accordance with the provisions of the patent statutes, we have hereindescribed the principle and operation of our invention, together withthe apparatus which we now consider to represent the best embodimentthereof, but we desire to have it understood that the apparatus shown isonly illustrative and that the'invention can be carried out by otherequivalent means. Also, while it is designed to use the various featuresand elements in the combination and relations described, some of thesemay be altered and others omitted without interfering with the moregeneral results outlined, and the invention extends to such use.

Having described our invention, what we claim and desire to secure byLetters Patent is:

1. In a rail flaw detector mechanism having means responsive to flaw andrail-marking means, means whereby said responsive means actuates saidrail-marking means to give the same size mark on the rail regardless ofthe length of time or size of the response of said responsive means,said last-named means including a series circuit comprising a gaseousdischarge tube having a plate, filament and grid, a discharge circuitfor said tube including a condenser and said rail-marking means, andmeans whereby said responsive means controls the potential of said gridto control the flow of current through said tube.

2. In a rail flaw detector mechanism having flaw responsive meansadapted to generate a potential when a flaw is encountered, andrailmarking means, means whereby said responsive means actuates saidrail-marking means to give the same size mark on the rail regardless ofthe length of time or size of the response of said responsive means,said last-named means including a series circuit comprising a gaseousdischarge tube having a plate, filament and grid, a discharge circuitfor said tube including a condenser and said rail-marking means, meansfor normally biasing said grid to prevent passage of current, and meanswhereby the potential generated by said responsive means is applied tosaid grid to permit current to pass.

3. In a rail fiaw detector mechanism having flaw responsive meansadapted to generate a potential when a flaw is'encountered andrailmarking means, means whereby said responsive means actuates saidrail-marking means to give the same size mark on the rail regardless ofthe length of time or size of the response of said responsive means,said last-named means including a series circuit comprising a gaseousdischarge tube having a plate, filament and grid, 2. discharge circuitfor said tube including a condenser and said rail-marking means, meansfor normally biasing said grid to prevent passage of current, and meanswhereby the potential generated by said responsive means is applied tosaid grid to permit current to pass to charge said condenser,road-bed-marking means, and means whereby the current passed by saidtube controls said road-bed-marking means.

4. In a rail flaw detector mechanism having flaw responsive meansadapted to generate a potential when a flaw is encountered andrailmarking means, means whereby said responsive means actuates saidrail-marking means to give the same size mark on the rail regardless ofthe length of time or size of the response of said responsive means,said last-named means including a series circuit comprising a gaseousdischarge tube having a plate, filament and grid, a discharge circuitfor said tube including a condenser and said rail-marking means, meansfor normally biasing said grid to prevent passage of current, and meanswhereby the potential generated by said responsive means is applied tosaid grid to permit current to pass to charge said condenser,road-bed-marking means, and means whereby the current passed by saidtube renders said roadbed-marking means efiective.

5. In a rail flaw detector mechanism having flaw responsive meansadapted to generate a potential when a flaw is encountered andrailmarking means, means whereby said responsive means actuates saidrail-marking means to give the same size marks on the rail regardless ofthe length of time or size of the response of said responsive means,said last-named means including a series circuit comprising a gaseousdischarge tube having a plate, filament and grid, a discharge circuitfor said tube including a condenser and said rail-marking means, meansfor normally biasing said grid to prevent passage oi current, and meanswhereby the potential generated by said responsive means is applied tosaid grid to permit current to pass to charge said condenser,road-bed-marking means, and means whereby the current passed by saidtube renders said road-bed-marking means efiective, said lastnamed meanscomprising a circuit having a source of current supply, a thermionictube having a plate, a filament and grid, means for normally biasingsaid grid to prevent passage of current, and means whereby the currentpassed by said discharge tube varies the bias on said last-named grid topermit current to pass.

6. In a rail flaw detector mechanism having flaw responsive meansadapted to generate a potential when a flaw is encountered andrailmarking means, means whereby said responsive means actuates saidrail marking means to give the same size mark on the rail regardless ofthe length of time or size of the response of said responsive means,said last-named means including a series circuit comprising a gaseousdischarge tube having a plate, filament and grid, a discharge circuitfor said tube including a con- .denser and said rail-marking means,means for normally biasing said grid to prevent passage of current, andmeans whereby the potential generated by said responsive means isapplied to said grid to permit current to pass to charge said condenser,a discharge circuit shunted around said condenser and including athermionic tube normally oilering high resistance, and means controlledby the discharge of said condenser for lowering the resistance of saidtube.

7. In a rail flaw detector mechanism having flaw responsive meansadapted to generate a potential when a flaw is encountered andrailmarking means, means whereby said responsive means actuates saidrail-marking means to give the same size mark on the rail regardless ofthe length of time or size of the response of said responsive means,said last-named means including a series circuit comprising a gaseousdischarge tube having a. plate, filament and grid, a discharge circuitfor said tube including a condenser and said rail-marking means, meansfor normally biasing said grid to prevent passage of current, and meanswhereby the potential generated by said responsive means is applied tosaid grid to permit current to pass to charge said condenser, adischarge circuit shunted around said condenser and including athermionic tube having a plate, filament and grid, means for normallybiasing said grid so that said last-named tube offers high resistance tothe flow of current, and means controlled by the discharge of saidcondenser for applying a potential to said last-named grid to lower theresistance of said tube.

8. In a rail flaw detector mechanism having fiaw responsive meansadapted to generate a potential when a flaw is encountered, andrailmarking means, means whereby said responsive means actuates saidrail marking means to give the same size mark on the rail regardless ofthe length of time or size of the response of said responsive means,said last-named means including a series circuit comprising a gaseousdischarge tube having a plate, filament and grid, a discharge circuitfor said tube including a condenser and said rail-marking means, meansfor normally biasing said grid to prevent passage of current, and meanswhereby the potential generated by said responsive means is applied tosaid grid to permit current to pass to charge said condenser,

, road-bed-marking means, a discharge circuit for said condenserincluding means for actuating said road-bed-marking means, means wherebysaid preceding means is rendered efiective when the current charges saidcondenser, means for accelerating the discharge of said condenser, andmeans whereby said accelerating means is rendered eiiective when saidcondenser begins to discharge through said circuit.

9. In a rail flaw detector mechanism having flaw responsive meansadapted to generate a potential when a flaw is encountered andrailmarking means, means whereby said responsive means actuates saidrail-marking means to give the same size mark on the rail regardless ofthe length of time or size of the response of said responsive means,said last-named means including a series circuit comprising a gaseousdischarge tube having a plate, filament and grid, a discharge circuitIor said tube including a condenser and said rail-marking means, meansfor normally biasing said grid to prevent passage of current, and meanswhereby the potential generated by said responsive means is applied tosaid grid to permit current to pass to charge said condenser, adischarge circuit for the condenser including a two-way control member,means

